2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/40738We explore the earth matter effects on the energy spectra of neutrinos from a supernova. We show that the observations of the energy spectra of $ν_e$ and $\barν_e$ from a galactic supernova may enable us to identify the solar neutrino solution, to determine the sign of $Δm^2_{32}$, and to probe the mixing matrix element $|U_{e3}|^2$ to values as low as $10^{-3}$. We point out scenarios in which the matter effects can even be established through the observation of the spectrum at a single detector.8 pages LaTeX, 2 eps figures, uses Rinton-P9x6.cls. Talk given at CICHEP '2001, Cairo, Egypt, January 2001High Energy Physics - Phenomenologytext